Light-emitting element with protective cushioning

ABSTRACT

A light-emitting element includes: a semiconductor light-emitting stack including a first semiconductor layer with a first conductivity, an active layer, and a second semiconductor layer with a second conductivity; a first conductive layer disposed on the semiconductor light-emitting stack and electrically connecting the second semiconductor layer; a first insulating layer on the first conductive layer; a second conductive layer disposed on the first insulating layer and electrically connecting the first semiconductor layer; a second insulating layer on the second conductive layer; a first pad and a second pad on the second conductive layer; and a cushion part disposed between the first pad and the second pad.

REFERENCE TO RELATED APPLICATION

This application claims the right of priority based on U.S. 62/092,422,filed on Dec. 16, 2014, and the content of which is hereby incorporatedby reference in the entirety.

TECHNICAL FIELD

The disclosure is related to a light-emitting element, and moreparticularly, a light-emitting element with a cushion part.

DESCRIPTION OF THE RELATED ART

During LED chip package process, LED chips are detached from a blue tapeby an ejector pin, picked and placed on a predetermined mounting placeone by one via a vacuum chuck. Referring to FIGS. 1A-2C, FIG. 1A shows atop view of a conventional flip chip LED 1. FIG. 1B shows across-sectional view of the conventional flip chip LED 1, attached on ablue tape 23, along a line A-A′ of FIG. 1A and an ejector pin 21 pushingthe blue tape 23 and the conventional flip chip LED 1. The ejector pin21 can punch through the blue tape 23 and press on a surface of theconventional flip chip LED 1. As shown in FIGS. 1A-1B, the conventionalflip chip LED 1 includes a light-emitting stack 10 including a p-typesemiconductor layer, a n-type semiconductor layer, and an active layerdisposed between the p-type semiconductor layer and the n-typesemiconductor layer (not shown), a first pad 15 electrically connectingthe n-type semiconductor layer, and a second pad 16 electricallyconnecting the p-type semiconductor layer. Herein, the ejector pin 21can be applied to the flip chip LED 1 to detach the flip chip LED 1 fromthe blue tape 23 which covers an entire top surface of the flip chip LED1. In detail, the ejector pin 21 is attached to a center region of theflip chip LED 1 located between the first pad 15 and the second pad 16called gap area 151 for lifting and detaching the flip chip LED 1 fromthe blue tape 23, and thus the flip chip LED 1 is damaged due to thedetaching.

FIG. 2A shows a picture of the conventional flip chip LED 1 damaged dueto the detaching, FIG. 2B shows an enlarged partial top view of region Cin FIG. 2A, and FIG. 2C shows an enlarged partial top view of region Din FIG. 2B. Since mechanical strength of the flip chip LED 1 is notstrong enough, when the ejector pin 21 pushes the flip chip LED 1, theejector pin 21 will damage the flip chip LED 1 and result in chip damagesuch as cracks 27 produced in the flip chip LED 1. When current injectsinto the flip chip LED 1, the crack damage causes short circuits in theflip chip LED 1. The reliability of the flip chip LED 1 will be affecteddue to the damage accordingly.

SUMMARY OF THE DISCLOSURE

A light-emitting element includes a semiconductor light-emitting stackhaving a first semiconductor layer with a first conductivity, an activelayer, and a second semiconductor layer with a second conductivity, afirst conductive layer disposed on the semiconductor light-emittingstack and electrically connecting the second semiconductor layer, afirst insulating layer disposed on the first conductive layer, a secondconductive layer disposed on the first insulating layer and electricallyconnecting the first semiconductor layer, a second insulating layer onthe second conductive layer, a first pad, a second pad, and a cushionpart. Herein, the first pad and the second pad are disposed on thesecond insulating layer, and a cushion part disposed between the firstpad and the second pad.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawing is included to provide easy understanding ofthe application, and is incorporated herein and constitutes a part ofthis specification. The drawing illustrates the embodiment of theapplication and, together with the description, serves to illustrate theprinciples of the application.

FIG. 1A shows a top view of a conventional flip chip LED.

FIG. 1B shows a cross-sectional view of the conventional flip chip LED,attached on a blue tape, along a line A-A′ of FIG. 1A and an ejector pinpushing the blue tape and the conventional flip chip LED.

FIG. 2A shows a picture of the conventional flip chip LED damaged due tothe detaching.

FIG. 2B shows an enlarged partial top view of region C in FIG. 2A.

FIG. 2C shows an enlarged partial top view of region D in FIG. 2B.

FIG. 3A shows a top view of a light-emitting element in accordance witha first embodiment of the application.

FIG. 3B shows a cross-sectional view of the light-emitting element alonga line E-E′ of FIG. 3A.

FIG. 4A shows a top view of a light-emitting element in accordance witha second embodiment of the application.

FIGS. 4B-4L show steps of a process flow of the light-emitting elementalong a line F-F′ of FIG. 4A.

FIG. 5 shows a cross-sectional view of a light-emitting element inaccordance with a third embodiment of the application.

FIG. 6A shows a top view of a light-emitting element in accordance witha fourth embodiment of the application.

FIG. 6B shows a cross-sectional view of the light-emitting element alonea line G-G′ of FIG. 6A.

FIG. 7A shows a top view of a light-emitting element in accordance witha fifth embodiment of the application.

FIG. 7B shows a cross-sectional view of the light-emitting element alonea line H-H′ of FIG. 7A.

FIG. 8A shows a top view of a light-emitting element in accordance witha sixth embodiment of the application.

FIG. 8B shows a cross-sectional view of the light-emitting element alonea line I-I′ of FIG. 8A.

FIG. 9A shows a top view of a light-emitting element in accordance witha seventh embodiment of the application.

FIG. 9B shows a cross-sectional view of the light-emitting element alonea line J-J′ of FIG. 9A.

FIG. 10A shows a top view of a light-emitting element in accordance withan eighth embodiment of the application.

FIG. 10B shows a cross-sectional view of the light-emitting elementalone a line K-K′ of FIG. 10A.

FIG. 11A shows an isometric view of a light-emitting element inaccordance with a ninth embodiment of the application.

FIG. 11B shows a top view of each layer of FIG. 11A.

FIG. 12A shows an isometric of a light-emitting element in accordancewith a tenth embodiment of the application.

FIG. 12B shows a top view of each layer of FIG. 12A.

FIG. 13A shows a top view of a light-emitting element in accordance withan eleventh embodiment of the application.

FIG. 13B shows a top view of a light-emitting element in accordance witha twelfth embodiment of the application.

FIG. 13C shows a top view of a light-emitting element in accordance witha thirteenth embodiment of the application.

FIG. 14 shows testing data related to short-circuit ratios oflight-emitting elements of the first embodiment and the conventionallight-emitting element.

DETAILED DESCRIPTION OF THE EMBODIMENTS

To better and concisely explain the application, the same name or thesame reference number given or appeared in different paragraphs orfigures along the specification should has the same or equivalentmeanings while it is once defined anywhere of the application.

The following shows the description of embodiments of the application inaccordance with the drawing.

Referring to FIGS. 3A-3B, FIG. 3A shows a top view of a light-emittingelement 3 in accordance with a first embodiment of the application. FIG.3B shows a cross-sectional view of the light-emitting element 3 along aline E-E′ of FIG. 3A. The light-emitting element 3 is adhered on a bluetape 23′ and an ejector pin 21′ presses on it through the blue tape 23′.As shown in FIGS. 3A-3B, the blue tape 23′ covers an entire top surfaceof the light-emitting element 3. The light-emitting element 3 includes asemiconductor light-emitting stack 30 on a substrate 25′, a firstconductive layer 31 on the semiconductor light-emitting stack 30, afirst insulating layer 32 on the first conductive layer 31, a secondconductive layer 33 on the first insulating layer 32 electricallyisolated from the first conductive layer 31, a second insulating layer34 on the second conductive layer 33, a first pad 35, a second pad 36,and a cushion part 37 interposed between the first insulating layer 32and the second insulating layer 34. The semiconductor light-emittingstack 30 includes a first semiconductor layer with a first conductivity,an active layer, and a second semiconductor layer with a secondconductivity (not shown). Herein the first conductive layer 31electrically connects the second semiconductor layer, and the secondconductive layer 33 electrically connects the first semiconductor layer.In the embodiment, a shape of the cushion part 37 in a top view can be arectangular shape, the material of the cushion part 37 can be metal, andthe cushion part 37 is electrically isolated from the first conductivelayer 31 and the second conductive layer 33. In another embodiment, thematerial of the cushion part can be insulating material. In a top view,the cushion part 37 overlaps with the first conductive layer 31, and ina cross-sectional view, the cushion part 37 is substantially coplanarwith and surrounded by the second conductive layer 33. The first pad 35and the second pad 36 electrically connect the first semiconductor layerand the second semiconductor layer via the second conductive layer 33and the first conductive layer 31, respectively. The cushion part 37 islocated between the first pad 35 and the second pad 36 in a top view asshown in FIG. 3A and interposed between the first insulating layer 32and the second insulating layer 34 in a cross-sectional view as shown inFIG. 3B.

Herein, the ejector pin 21′ penetrates the blue tape 23′ and then pushthe light-emitting element 3 to detach the light-emitting element 3 fromthe blue tape 23′. Because of the cushion part 37 integrated in thelight-emitting element 3, while the ejector pin 21′ detaches thelight-emitting element 3 from the blue tape 23′ via pushing the cushionpart 37, cracks 27′ can be produced nearby the cushion part 37 but notto form conductive paths between the first conductive layer 31 and thesecond conductive layer 33. Accordingly, in the first embodiment, thecushion part 37 and the first conductive layer 31 are electricallyisolated from the second conductive layer 33. Short circuits in thelight-emitting element 3 will not happen accordingly.

FIG. 4A shows a top view of a light-emitting element 4 in accordancewith a second embodiment of the application. FIGS. 4B-4L show steps of aprocess flow of the light-emitting element 4 and cross-sectional viewsalong a line F-F′ of FIG. 4A. FIG. 4B shows a step of forming asemiconductor light-emitting stack 40 on a substrate 425. In this step,the substrate 425 is provided and the semiconductor light-emitting stack40 is formed on the substrate 425. The substrate 425 includes atransparent substrate. A material of the substrate 425 includestransparent material which is transparent with respect to the lightemitted from the semiconductor light-emitting stack 40, such as galliumarsenide (GaAs), gallium phosphide (GaP), gallium nitride (GaN),sapphire, diamond, glass, quartz, acrylic, zinc oxide (ZnO), or aluminumnitride (AlN). Additionally, the substrate 425 can be a conductivesubstrate or a non-conductive substrate based on the material of thesubstrate itself or the impurities doped in the substrate. The substrate425 can be a substrate for epitaxial growth, optionally have a patternedupper surface which can improve epitaxy quality of the semiconductorlight-emitting stack 40, and scatter the light emitted from thesemiconductor light-emitting stack 40.

For improving the quality of the semiconductor light-emitting stack 40,a buffer layer (not shown) can be formed between the substrate 425 andthe semiconductor light-emitting stack 40. The semiconductorlight-emitting stack 40 includes a first semiconductor layer 401, asecond semiconductor layer 403, and an active layer 402 formed betweenthe first semiconductor layer 401 and the second semiconductor layer403. Herein, the first semiconductor layer 401 and the secondsemiconductor layer 403 are with different conductivities, electricity,polarities, or dopants for providing electrons and holes. The polaritycan be an n-type polarity or p-type polarity for supplying electrons andholes, respectively so that electrons and holes can combine in theactive layer 402 to emit light. For example, the first semiconductorlayer 401 can be an n-type semiconductor layer and the secondsemiconductor layer 403 can be a p-type semiconductor layer.

The material of the semiconductor light-emitting stack 40 includesaluminum gallium indium phosphide (AlGaInP) base or aluminum galliumindium nitride (AlGaInN) base. The active layer 402 includes singleheterostructure (SH), double heterostructure (DH), double-side doubleheterostructure (DDH), or multi-quantum well (MQW) structure.Specifically, the active layer 402 includes i-type, p-type, or n-typesemiconductor. The active layer 402 emits light when electrical currentpasses through the semiconductor light-emitting stack 40. When theactive layer 402 includes AlGaInP based material, the active layer 402emits amber series light, such as red light, orange light, or yellowlight; when the active layer 402 includes AlGaInN based material, theactive layer 402 emits blue, green or UV light. The present embodimentillustrates the semiconductor light-emitting stack 40 with aluminumgallium indium nitride (AlGaInN) based material.

FIG. 4C shows a step of forming a plurality of first depressions 48.Referring to FIGS. 4A-4C, the plurality of first depressions 48 isformed in the semiconductor light-emitting stack 40 through opticallithography and etching processes. Each of the first depressions 48penetrates from an upper surface 403 a of the second semiconductor layer403 into the second semiconductor layer 403, the active layer 402, andthe first semiconductor layer 401 to expose an upper surface 401 a ofthe first semiconductor layer 401. In the embodiment, the plurality offirst depressions 48 is a plurality of vias.

FIG. 4D shows a step of forming a first conductive layer 41 having anupper surface 41 a. Firstly, the first conductive layer 41 is formed onthe upper surfaces 401 a and 403 a and then a portion of the firstconductive layer 41 is removed in accordance with the plurality of firstdepressions 48 through optical lithography and etching processes.Finally, the first conductive layer 41 is patterned and formed on theupper surface 403 a of the second semiconductor layer 403. In anotherembodiment, the plurality of first depressions 48 can be formed afterforming the first conductive layer 41 on the semiconductorlight-emitting stack 40. The etching steps of the semiconductorlight-emitting stack 40 and the first conductive layer 41 can beperformed at the same time, that is etching parts of the semiconductorlight-emitting stack 40 and the first conductive layer 41 at the samestep and then the plurality of first depressions 48 is formed to exposethe upper surface 401 a. In the embodiment, the first conductive layer41 electrically connects the second semiconductor layer 403.Additionally, the first conductive layer 41 has electrically contactwith the second semiconductor layer 403 and can be metal material, suchas, nickel (Ni), platinum (Pt), palladium (Pd), silver (Ag), or chromium(Cr), aluminum (Al), titanium (Ti), gold (Au), or combinations thereof.In one embodiment, the first conductive layer 41 can includes aplurality of layers, for example, a transparent conductive layer (notshown), a reflective layer (not shown) formed on the transparentconductive layer, and a barrier layer (not shown) formed on and coveringthe reflective layer to prevent migration or oxidization of thereflective layer causing a decrease in the reflectivity. The transparentconductive layer electrically connects the second semiconductor layer403, and the reflective layer electrically connects the transparentconductive layer. Light emitting from the active layer 402 can bereflected to the substrate 425 by the reflective layer, and extractedfrom a surface of the substrate 425 opposite to the active layer 402.The material of the transparent conductive layer includes ITO (tin-dopedindium oxide), AZO (aluminum-doped ZnO), GZO (gallium-doped zinc oxide),or IZO (indium-doped zinc oxide), and so forth; the material of thereflective layer includes silver, gold, copper, or aluminum, and soforth; the material of the barrier layer includes metal materials, forexample, titanium (Ti), tungsten (W), aluminum (Al), indium (In),stannum (Sn), nickel (Ni), platinum (Pt), or an alloy including at leastone metal selected from the group consisting of Ti, W, Al, In, Sn, Ni,and Pt as described above. Additionally, the barrier layer may include ametal stack such as Ti/Al/Ti/W disposed on the reflective layer.

FIG. 4E shows a step of forming a first insulating layer 42. Referringto FIG. 4E, the first insulating layer 42 is formed on an upper surface41 a of the first conductive layer 41, side walls of the semiconductorlight-emitting stack 40, the first conductive layer 41 and the firstdepressions 48, and the upper surface 401 a of the first semiconductorlayer 401 in the first depressions 48. The material of the firstinsulating layer 42 includes transparent material, for example, SiO₂,TiO₂, or Si₃N₄. Moreover, the first insulating layer 42 can be formed byevaporating, sputtering, or spin-on glass (SOG) coating.

FIG. 4F shows a step of removing portions of the first insulating layer42 to form second depressions 428 and 428′. After forming the firstinsulating layer 42, portions of the first insulating layer 42 on theupper surface 401 a of the first semiconductor layer 401 and the uppersurface 41 a of the first conductive layer 41 are removed throughoptical lithography and etching processes to form the second depressions428 and 428′, respectively. The second depressions 428 penetrate from anupper surface 42 a of the first insulating layer 42 into the firstinsulating layer 42 and expose the upper surface 401 a of the firstsemiconductor layer 401. The second depression 428′ penetrates from anupper surface 42 a of the first insulating layer 42 into the firstinsulating layer 42 and exposes the upper surface 41 a of the firstconductive layer 41. In the embodiment, the second depressions 428 and428′ are vias.

FIGS. 4G and 4H show steps of forming a second conductive layer 43 andthird depressions 438 and 438′. Firstly, the second conductive layer 43,having an upper surface 43 a, is formed to fill the second depressions428 and 428′ and covers a portion of the upper surface 42 a of the firstinsulating layer 42. Herein, the second conductive layer 43 filling inthe second depressions 428 electrically connects the first semiconductorlayer 401. Then, a portion of the second conductive layer 43 located ata center region of the light-emitting element 4 is removed throughoptical lithography and etching processes to form the third depressions438′. Herein, the third depression 438′ penetrates from the uppersurface 43 a of second conductive layer 43 to the upper surface 42 a.Moreover, a portion of the second conductive layer 43 filling in thesecond depression 428′ is also removed through the same opticallithography and etching processes to form the third depressions 438 sothat the upper surface 41 a of the first conductive layer 41 and theupper surface 42 a of the first insulating layer 42 are exposed. In theembodiment, the third depression 438 connects and is aligned with thesecond depression 428′, and has a shape corresponding to the alignedsecond depression 428′ in a top view. The third depression 438′ isoverlapped with the center region of the light-emitting element 4 in atop view. The material of the second conductive layer 43 can be metalmaterial, such as, nickel (Ni), platinum (Pt), palladium (Pd), silver(Ag), chromium (Cr), aluminum (Al), titanium (Ti), gold (Au), orcombinations thereof.

FIG. 4I shows a step of forming a cushion part 47. Referring to FIGS. 4Aand 4H, the cushion part 47 is formed on the upper surface 42 a of thefirst insulating layer 42 which is exposed by the third depressions 438′and located at the center region of the light-emitting element 4.Further, the cushion part 47 can be surrounded by the second conductivelayer 43 and be electrically and physically isolated from the firstconductive layer 41 and the second conductive layer 43. In theembodiment, a shape of the cushion part 47 in a top view can be arectangular shape. A shape of the third depressions 438′ in a top viewcan be a rectangular shape or an elliptical shape. The material of thecushion part 47 can be metal and the same as a material of the secondconductive layer 43, such as, nickel (Ni), platinum (Pt), palladium(Pd), silver (Ag), chromium (Cr), aluminum (Al), titanium (Ti), gold(Au), or combinations thereof. In another embodiment, the material ofthe cushion part 47 can be insulating material or transparent material,for example, SiO₂, TiO₂, or Si₃N₄, and the cushion part 47 can be formedby evaporating, sputtering, or spin-on glass (SOG) coating. Thethickness of the cushion part 47 can be designed to bear the detachingstrength of the ejector pin to prevent damages of the light-emittingstack during the ejector pin detaching process. In detail, the cushionpart 47 with the designed thickness can prevent short circuits betweenthe first conductive layer 41 and the second conductive layer 43 in thelight-emitting element 4 due to the cracks of the first insulating layer42 occurring in the ejector pin detaching process.

FIG. 4J shows a step of forming a second insulating layer 44. Referringto FIG. 4J, the second insulating layer 44 is formed on the uppersurface 43 a, side walls of the second conductive layer 43, and theupper surface 41 a of the first conductive layer 41. In detail, thesecond insulating layer 44 covers the cushion part 47, and fills intothe third depressions 438 and 438′. In one embodiment, the secondinsulating layer 44 can fill up at least one of the third depressions438 and 438′.

FIG. 4K shows a step of removing portions of the second insulating layer44 to form a plurality of fourth depressions 448 and 448′. After formingthe second insulating layer 44, a portion of the second insulating layer44, on the upper surface 43 a of the second conductive layer 43, isremoved through optical lithography and etching processes to form thefourth depression 448 and expose the upper surface 43 a of the secondconductive layer 43. In addition, the second insulating layer 44 fillingin the third depression 438 is also removed to expose the upper surface41 a of the first conductive layer 41 through the same opticallithography and etching processes and then the fourth depression 448′ isformed accordingly. Herein, the fourth depression 448 penetrates from anupper surface 44 a of the second insulating layer 44 to expose the uppersurface 43 a of the second conductive layer 43 and the fourth depression448′ expose the second depression 428′ so as to expose the upper surface41 a of the first conductive layer 41. As shown in FIG. 4K, the cushionpart 47 is interposed between and encapsulated by the first insulatinglayer 42 and the second insulating layer 44 in a cross-sectional view.

FIG. 4L shows a step of forming a first pad 45 and a second pad 46. Thefirst pad 45 and the second pad 46 are formed on the second insulatinglayer 44. Herein, the first pad 45 is formed on one side of thesubstrate 425 in a top view and fills in the fourth depression 448 forcontacting the second conductive layer 43 so as to electrically connectthe first semiconductor layer 401. The second pad 46 is formed onanother side of the substrate 425 in a top view and fills in the fourthdepression 448′ for contacting the first conductive layer 41 so as toelectrically connect the second semiconductor layer 403. When thelight-emitting element 4 electrically connects a power supply (notshown) via the first pad 45 and the second pad 46, the active layer 402emits light. As shown in the FIGS. 4A and 4L, the cushion part 47 isdisposed between the first pad 45 and the second pad 46. As the reasonmentioned above, when an ejector pin (not shown) pushes thelight-emitting element 4, short circuits will not happen due to theprotection of the cushion part 47.

Referring to FIG. 5, it shows a cross-sectional view of a light-emittingelement 5 in accordance with a third embodiment of the application. Thestructure of light-emitting element 5 is similar to that of thelight-emitting element 4. For clarifying, in the third embodiment,similar components are labeled by the same reference numbers and thedescriptions thereof are omitted herein. The differences between thelight-emitting element 5 and the light-emitting element 4 are, in thethird embodiment, a second conductive layer 43′ covers sidewalls/surfaces of a first insulating layer 42, outer edges of the secondconductive layer 43′ excess over outer edges of an active layer 402 anda second semiconductor layer 403 of a semiconductor light-emitting stack40 in a cross-sectional view as shown in FIG. 5, and the outer edges ofthe second conductive layer 43′ physically contacts a firstsemiconductor layer 401 of the semiconductor light-emitting stack 40 toform a periphery contacting area. Accordingly, a contact area betweenthe second conductive layer 43′ and the first semiconductor layer 401 ofthe third embodiment is greater than that of the second embodiment. Theelectrical characteristic of the light-emitting element 5, such asforward voltage, can be better than that of light-emitting element 4.Similarly, when the light-emitting element 5 electrically connects apower supply via a first pad 45 and a second pad 46, the active layer402 emits light.

Referring to FIGS. 6A-6B, FIG. 6A shows a top view of a light-emittingelement 6 in accordance with a fourth embodiment of the application andFIG. 6B shows a cross-sectional view of the light-emitting element 6along a line G-G′ of FIG. 6A. As shown in FIGS. 6A-6B, thelight-emitting element 6 includes a semiconductor light-emitting stack60 on a substrate 625, a first conductive layer 61 on the semiconductorlight-emitting stack 60, a first insulating layer 62 on the firstconductive layer 61, a second conductive layer 63 on the firstinsulating layer 62, a second insulating layer 64 on the secondconductive layer 63, a first pad 65, a second pad 66, a cushion part 67between the first pad 65 and the second pad 66 in a top view, aplurality of first depressions 68, second depressions 628 and 628′,third depressions 638 and 638′, and fourth depressions 648 and 648′.When the light-emitting element 6 electrically connects a power supplyvia the first pad 65 and the second pad 66, the active layer 602 emitslight.

The structure of the fourth embodiment is similar to that of the secondembodiment. The difference between the fourth embodiment and the secondembodiment is that the material of the cushion part 67 is insulatingmaterial and can be the same as the material of the first insulatinglayer 62 or the second insulating layer 64. In the embodiment, thecushion part 67 is formed in a center region of the light-emittingelement 6 in a top view and interposed between the first insulatinglayer 62 and the second insulating layer 64 to prevent the crack damage.When an ejector pin (not shown) pushes the center region of thelight-emitting element 6, the cushion part 67 can absorb part of thestrength from the ejector pin to prevent from conductive paths occurringbetween the first conductive layer 61 and the second conductive layer63, and short circuits due to the conductive paths will not happenaccordingly.

Referring to FIGS. 7A-7B, FIG. 7A shows a top view of a light-emittingelement 7 in accordance with a fifth embodiment of the application, andFIG. 7B shows a cross-sectional view of the light-emitting element 7along a line H-H′ of FIG. 7A. The light-emitting element 7 includes asemiconductor light-emitting stack 70, having a first semiconductorlayer 701 with a first conductivity, an active layer 702, and a secondsemiconductor layer 703 with a second conductivity, on a substrate 725,a first conductive layer 71 on the semiconductor light-emitting stack70, a first insulating layer 72 on the first conductive layer 71, asecond conductive layer 73 on the first insulating layer 72, a secondinsulating layer 74 on the second conductive layer 73, a first pad 75, asecond pad 76, a cushion part 77 between the first pad 75 and the secondpad 76, a plurality of first depressions 78, second depressions 728 and728′, third depressions 738 and 738′, and fourth depressions 748 and748′. When the light-emitting element 7 electrically connects a powersupply via the first pad 75 and the second pad 76, the active layer 702emits light.

The structure of the fifth embodiment is similar to that of the secondembodiment. Similar components are labeled with similar referencenumeral and descriptions therewith are omitted herein. Similarly, ashape of the cushion part 77 in a top view includes a rectangular shape.However, the difference between the fifth embodiment and the secondembodiment is the location of the cushion part 77. In the embodiment, inorder to prevent the crack damage, the cushion part 77 is formed on thesecond insulating layer 74. In detail, the second insulating layer 74are formed on the first insulating layer 72, and fills into the thirddepression 738′, overlapped with the center region of the light-emittingelement 7. When an ejector pin (not shown) pushes the center region ofthe light-emitting element 7, the cushion part 77 can absorb part of thestrength from the ejector pin to prevent from conductive paths occurringbetween the first conductive layer 71 and the second conductive layer73, and short circuits due to the conductive paths will not happenaccordingly.

Referring to FIGS. 8A-8B, FIG. 8A shows a top view of a light-emittingelement 8 in accordance with a sixth embodiment of the application andFIG. 8B shows a cross-sectional view of the light-emitting element 8along a line I-I′ of FIG. 8A. As shown in FIGS. 8A-8B, thelight-emitting element 8 includes a semiconductor light-emitting stack80, having a first semiconductor layer 801 with a first conductivity, anactive layer 802, and a second semiconductor layer 803 with a secondconductivity, on a substrate 825, a first conductive layer 81 on thesemiconductor light-emitting stack 80, a first insulating layer 82 onthe first conductive layer 81, a second conductive layer 83 on the firstinsulating layer 82, a second insulating layer 84 on the secondconductive layer 83, a first pad 85, a second pad 86, a cushion part 87between the first pad 85 and the second pad 86 in a top view, and aplurality of first depressions 88, second depressions 828 and 828′,third depressions 838, and fourth depressions 848 and 848′. When thelight-emitting element 8 electrically connects a power supply via thefirst pad 85 and the second pad 86, the active layer 802 emits light.

The structure of the sixth embodiment is similar to that of the secondembodiment. Similar components are labeled with similar referencenumeral and descriptions therewith are omitted herein. Similarly, ashape of the cushion part 87 in a top view includes a rectangular shape.However, the difference between the sixth embodiment and the secondembodiment is the relative positions among the cushion part, the secondinsulating layer, and the second conductive layer, and the relativeprocess. Referring to the light-emitting element 4 of the secondembodiment, the cushion part 47 is formed in the third depression 438′,overlapped with a center region of the light-emitting element 4 in a topview, and the cushion part 47 is disposed between the second insulatinglayer 44 and the second conductive layer 43. Referring to thelight-emitting element 8 of the embodiment, the second conductive layer83, the second insulating layer 84, and the cushion part 87 are formedin a center region of the light-emitting element 8 in sequence. Indetail, there is no third depression formed in the second conductivelayer 83 to expose an upper surface of the first insulating layer 82,the second insulating layer 84 is located right above the secondconductive layer 83. The cushion part 87 is directly formed on thesecond insulating layer 84 in a cross-sectional view. Moreover, as shownin FIG. 8B, the second conductive layer 83 is continuously overlappedwith the center region. Additionally, when an ejector pin (not shown)pushes the center region of the light-emitting element 8, the cushionpart 87 can absorb part of the strength from the ejector pin to preventfrom conductive paths occurring between the first conductive layer 81and the second conductive layer 83, and short circuits due to theconductive paths will not happen accordingly.

Referring to FIGS. 9A-9B, FIG. 9A shows a top view of a light-emittingelement 9 in accordance with a seventh embodiment of the application andFIG. 9B shows a cross-sectional view of the light-emitting element 9along a line J-J′ of FIG. 9A. As shown in FIGS. 9A-9B, thelight-emitting element 9 includes a semiconductor light-emitting stack90, having a first semiconductor layer 901 with a first conductivity, anactive layer 902, and a second semiconductor layer 903 with a secondconductivity, on a substrate 925, a first conductive layer 91 on thesemiconductor light-emitting stack 90, a first insulating layer 92 onthe first conductive layer 91, a cushion part 97 on the first conductivelayer 91 and interposed in the first insulating layer 92 in across-sectional view, a second conductive layer 93 on the firstinsulating layer 92, a second insulating layer 94 on the secondconductive layer 93, a first pad 95, a second pad 96, and a plurality offirst depressions 98, second depressions 928 928′, and 928″, thirddepressions 938 and 938′, and fourth depressions 948 and 948′. Herein, ashape of the cushion part 97 in a top view includes a rectangular shape.

The structure of the embodiment is similar to that of the secondembodiment. Similar components are labeled with similar referencenumeral and descriptions therewith are omitted herein. In theembodiment, steps and sequences of forming the semiconductorlight-emitting stack 90 are similar to that of the second embodiment,and descriptions therewith are omitted herein. The differences betweenthe embodiment and the second embodiment are the positions of seconddepressions, the cushion part, and the third depressions, and therelative forming steps. Referring to the light-emitting element 9 of theembodiment, in the step of forming the second depressions 928, 928′, and928″, it further includes removing the first insulating layer 92overlapped with a center region of the light-emitting element 9 to formthe second depression 928″. Then, the cushion part 97 is formed in thesecond depression 928″ and contacts the first conductive layer 91.Afterwards, the second conductive layer 93 and the third depressions 938and 938′ in the second conductive layer 93 are formed, and then thesecond insulating layer 94 fills the second depression 928″ and thethird depression 938′ to cover the cushion part 97.

The material of the cushion part 97 can be the same as a material of thefirst conductive layer 91 or the second conductive layer 93, such as,nickel (Ni), platinum (Pt), palladium (Pd), silver (Ag), chromium (Cr),aluminum (Al), titanium (Ti), gold (Au), or combinations thereof. Inanother embodiment, the material of the cushion part 97 can beinsulating material or transparent material, such as SiO₂, TiO₂, orSi₃N₄, and the cushion part 97 can be formed by evaporating, sputtering,or spin-on glass (SOG) coating. In the embodiment, when an ejector pin(not shown) pushes the center region of the light-emitting element 9,the cushion part 97 can absorb part of the strength from the ejector pinto prevent from conductive paths occurring between the first conductivelayer 91 and the second conductive layer 93, and short circuits due tothe conductive paths will not happen accordingly.

Referring to FIGS. 10A-10B, FIG. 10A shows a top view of alight-emitting element 10′ in accordance with an eighth embodiment ofthe application and FIG. 10B shows a cross-sectional view of thesemiconductor light-emitting element 10′ along a line K-K′ of FIG. 10A.As shown in FIGS. 10A-10B, the light-emitting element 10′ includes asemiconductor light-emitting stack 100′, having first semiconductorlayer 1001′ with a first conductivity, an active layer 1002′, and asecond semiconductor layer 1003′ with a second conductivity, on thesubstrate 1025′, a first conductive layer 101′ on the semiconductorlight-emitting stack 100′, a first insulating layer 102′ on the firstconductive layer 101′, a second conductive layer 103′ on the firstinsulating layer 102′, a second insulating layer 104′ on the secondconductive layer 103′, a first pad 105′, a second pad 106′, a cushionpart 107′ between the first insulating layer 102′ and the secondinsulating layer 104′, and a plurality of first depressions 108′, seconddepressions 1028′ and 1028″, third depressions 1038′ and 1038″, andfourth depressions 1048′ and 1048″. When the light-emitting element 10′electrically connects a power supply via the first pad 105′ and thesecond pad 106′, the active layer 1002′ emits light.

The structure of the eighth embodiment is similar to that of the secondembodiment. Similar components are labeled with similar referencenumeral and descriptions therewith are omitted herein. However, thedifference between the eighth embodiment and the second embodiment isstructures of the third depressions and steps of forming the thirddepressions. Referring to the light-emitting element 4 of the secondembodiment, the shapes of the third depressions 438 and 438′ are acircle and an ellipse, respectively. In the eighth embodiment, in thestep of forming the third depression 1038″, a portion of the secondconductive layer 103′ is removed and the shape of the removed portion ofsecond conductive layer 103′ is irregular. The shape of the thirddepressions 1038″ corresponds to that of the removed portion of secondconductive layer 103′ with the irregular shape. The cushion part 107′with a rectangular shape is formed in the third depressions 1038″,covered by the second insulating layer 104′, disposed between the firstinsulating layer 102′ and the second insulating layer 104′, and locatedin a center region of the light-emitting element 10′. When an ejectorpin (not shown) pushes the center region of the light-emitting element10′ for detaching the light-emitting element 10′ from a blue tape, thecushion part 107′ can absorb part of the strength from the ejector pinto prevent from conductive paths occurring between the first conductivelayer 101′ and the second conductive layer 103′, and short circuits dueto the conductive paths will not happen accordingly.

Referring to FIGS. 11A-11B, FIG. 11A shows an isometric view of alight-emitting element 11′ in accordance with a ninth embodiment of theapplication, FIG. 11B shows a top view of each layer of thelight-emitting element 11′ in FIG. 11A. As shown in FIGS. 11A-11B, thelight-emitting element 11′ includes a semiconductor light-emitting stack110′, having a first semiconductor layer, an active layer and a secondsemiconductor layer (not shown in FIGS. 11A-11B), on a substrate 1125, afirst conductive layer 111′ on the semiconductor light-emitting stack110′, a first insulating layer 112′ on the first conductive layer 111′,a second conductive layer 113′ and a cushion part 117′ on the firstinsulating layer 112′, a second insulating layer 114′ on the secondconductive layer 113′, and a first pad 115′ and a second pad 116′ on thesecond insulating layer 114′ respectively.

Steps of forming the light-emitting element 11′ includes forming thesemiconductor light-emitting stack 110′ on the substrate 1125 andforming depressions 118′ in the semiconductor light-emitting stack 110′.Herein, the semiconductor light-emitting stack 110′ is epitaxially grownon the substrate 1125 and portions of the semiconductor light-emittingstack 110′ are etched away to form the depressions 118′. In theembodiment, the depressions 118′ penetrate into the second semiconductorlayer and the active layer from an upper surface of the semiconductorlight-emitting stack 110′ to expose an upper surface of the firstsemiconductor layer. Each of these layers of the semiconductorlight-emitting stack 110′ may include a number of sub-layers that varyin composition with respect to one another. The active layer can beconstructed from multiple InGaN layers separated by GaN layers. An uppersurface of the second semiconductor layer can be roughened by a suitableetching process. When the light-emitting element 11′ electricallyconnects a power supply via the first pad 115′ and the second pad 116′,the active layer emits light.

Referring to FIGS. 11A-11B, the steps of forming the light-emittingelement 11′ further include forming an insulating layer 11 a′ on thesemiconductor light-emitting stack 110′ before forming the firstconductive layer 111′. Herein, the insulating layer 11 a′ includes asquare ring-like region 11 a 1′ in a top view located on the edges ofthe semiconductor light-emitting stack 110′ and several circle ring-likeregions 11 a 2′ corresponding to the positions of the depressions 118′.The square ring-like region 11 a 1′ covers the sidewall of the activelayer and the second semiconductor layer. The circle ring-like regions11 a 2′ cover the sidewalls of the depressions 118′ and expose portionsof the upper surface of the first semiconductor layer in the depressions118′. The step of exposing the upper surface of the first semiconductorlayer in the depressions 118′ can be achieved via the etching andlithography processes.

The first conductive layer 111′ includes a first layer 1110′ havingdepressions 111 c′ and a second layer 1112′ having depressions 111 d′.The first layer 1110′ can be made of ITO, is formed on and covers asurface of the semiconductor light-emitting stack 110′ and is devoid offilling in the depressions 118′, and the second layer 1112′ is formed onthe first layer 1110′ and is devoid of filling in the depressions 111c′. The second layer 1112′ can be a mirror layer, for example, silver,and able to reflect light from the active layer. The first layer 1110′and the second layer 1112′ can be deposited over the semiconductorlight-emitting stack 110′ and electrically connect the secondsemiconductor layer.

After forming the first layer 1110′ and the second layer 1112′, thefirst insulating layer 112′ is formed on the second layer 1112′. Herein,the first insulating layer 112′ is patterned as shown in FIG. 11B andincludes a plurality of depressions 1121′ and 1123′. In the step offorming the first insulating layer 112′, the first insulating layer 112′is formed on the second layer 1112′ and covers side surfaces of thecircle ring-like regions 11 a 2′, side surfaces of the depressions 111c′ of the first layer 1110′, and side surfaces of the depressions 111 d′of the second layer 1112′. The first insulating layer 112′ is devoid ofcovering the upper surface of the first semiconductor layer exposed bythe circle ring-like regions 11 a 2′ to form the depressions 1121′. Thestep of forming the depressions 1121′ and 1123′ can be achieved by theetching and lithography processes. In another embodiment, the circlering like region 11 a 2′ and the depressions 1121′ of the firstinsulating layer 112′ exposing the upper surface of the firstsemiconductor layer in the depressions 118′ can be achieved at the sameetching and lithography processes.

Next, the second conductive layer 113′ with depressions 1131′ and 1133′and the cushion part 117′ are formed on the first insulating layer 112′at the same step. A portion of the second conductive layer 113′ fillsinto the depressions 1121′ to electrically and physically connect theupper surface of the first semiconductor layer. A center region of thesecond conductive layer 113′ is removed to form the rectangularring-like depression 1131′ and portions of the second conductive layer113′ are removed to form the depressions 1133′. In the embodiment, thecushion part 117′ is formed in the depression 1131′ and surrounded bythe second conductive layer 113′. The cushion part 117′ is formed on thecenter region of the light-emitting element 11′ in a top view, andelectrically isolated from the second conductive layer 113′. After thesecond conductive layer 113′ and the cushion part 117′ are formed, thesecond insulating layer 114′ is formed on the second conductive layer113′ and the cushion part 117′ and includes a plurality of depressions1141′ and 1143′. The depressions 1141′ expose the second conductivelayer 113′. The second insulating layer 114′ fills into the depressions1133′ and 1123′, covers side surfaces thereof to form the depressions1143′. Finally, the first pad 115′ and the second pad 116′ are formed onthe second insulating layer 114′. Herein, the first pad 115′electrically connects the second conductive layer 113′ via thedepressions 1141′, and the second pad 116′ electrically connects thefirst conductive layer 111′ via the depressions 1143′ to provideexternal contacts for powering the semiconductor light-emitting stack110′. Similarly, when an ejector pin (not shown) pushes the centerregion of the light-emitting element 11′, the cushion part 117′ canabsorb part of the strength from the ejector pin to prevent fromconductive paths occurring between the first conductive layer 111′ andthe second conductive layer 113′, and short circuits due to theconductive paths will not happen accordingly.

Referring to FIGS. 12A-12B, FIG. 12A shows an isometric view of alight-emitting element 12′ in accordance with a tenth embodiment of theapplication and FIG. 12B shows top views of each layers of FIG. 12A. Asshown in FIGS. 12A-12B, the light-emitting element 12′ includes asemiconductor light-emitting stack 120′, having a first semiconductorlayer, an active layer and a second semiconductor layer (not shown inFIGS. 12A-12B) formed on a substrate 1225 in sequence, and depressions128′; an insulating layer 12 a′, including a square ring-like region 12a 1′ in a top view located on the edges of the semiconductorlight-emitting stack 120′ and several circle ring-like regions 12 a 2′covering the sidewalls of the depressions 128′; a first conductive layer121′ having a first layer 1210′ with depressions 121 c′ and a secondlayer 1212′ with depressions 121 d′ on the semiconductor light-emittingstack 120′; a first insulating layer 122′ with depressions 1221′ and1223′ on the first conductive layer 121′; a cushion part 127′ and asecond conductive layer 123′ with depressions 1231′ and 1233′ on thefirst insulating layer 122′; a second insulating layer 124′ withdepressions 1241′ and 1243′ on the second conductive layer 123′; and afirst pad 125′ and a second pad 126′ on the second insulating layer124′. In the embodiment, a shape of the cushion part 127′ in a top viewincludes a rectangular shape. Additionally, steps of forming thelight-emitting element 12′ are similar to that of the light-emittingelement 11′. For clarifying, similar descriptions are omitted herein.

Similarly, when an ejector pin (not shown) pushes the center region ofthe light-emitting element 12′, the cushion part 127′ can absorb part ofthe strength from the ejector pin to prevent from conductive pathsoccurring between the first conductive layer 121′ and the secondconductive layer 123′, and short circuits due to the conductive pathswill not happen accordingly.

FIG. 13A shows a top view of a light-emitting element 13′ in accordancewith an eleventh embodiment of the application. The light-emittingelement 13′ includes a semiconductor light-emitting stack 130′ on asubstrate 1325, a first conductive layer 131′ on the semiconductorlight-emitting stack 130′, a first insulating layer (not shown) on thefirst conductive layer 131′, a second conductive layer 133′ on the firstinsulating layer, a second insulating layer (not shown) on the secondconductive layer 133′, a first pad 135′, a second pad 136′, and acushion part 137′ electrically connects the first conductive layer 131′.Herein, a shape of the cushion part 137′ in a top view includes arectangular shape. The structure and material of the cushion part 137′is similar as that of the cushion part 97 in the seventh embodiment, anda detailed description is omitted herein.

FIG. 13B shows a top view of a light-emitting element 14′ in accordancewith a twelfth embodiment of the application. The light-emitting element14′ includes a semiconductor light-emitting stack 140′ on a substrate1425, a first conductive layer (not shown) on the semiconductorlight-emitting stack 140′, a first insulating layer (not shown) on thefirst conductive layer, a second conductive layer 143′ with an irregularshape formed on the first insulating layer, a second insulating layer(not shown) on the second conductive layer 143′, a first pad 145′, asecond pad 146′, and a cushion part 147′ formed in a center regionwithout being covered by the second conductive layer 143′. At least aportion of the first insulating layer and the second insulating layerare formed in a center region of the light-emitting element 14′ and thematerial of the cushion part 147′ is the same as that of the firstinsulating layer or the second insulating layer. The structure,location, and material of the cushion part 147′ are similar as that ofthe cushion part 67 in the fourth embodiment, and a detailed descriptionis omitted herein.

FIG. 13C shows a top view of a light-emitting element 15′ in accordancewith a thirteenth embodiment of the application. The light-emittingelement 15′ includes a semiconductor light-emitting stack 150′ on asubstrate 1525, a first conductive layer (not shown) on thesemiconductor light-emitting stack 150′, a first insulating layer (notshown) on the first conductive layer, a second conductive layer 153′ onthe first insulating layer, a second insulating layer (not shown) on thesecond conductive layer 153′, a first pad 155′, a second pad 156′, and acushion part 157′. The cushion part 157′ is formed on the secondinsulating layer and located in a center region without being covered bythe second conductive layer 153′. In the embodiment, a portion of thesecond conductive layer 153′ is removed and the shape of the removedportion of the second conductive layer 153′ is irregular. A shape ofcushion part 157′ corresponds to the shape of the removed portion of thesecond conductive layer 153′ and includes an irregular shape. Similarly,when an ejector pin (not shown) pushes a center region of thelight-emitting element 15′, the cushion part 157′ can absorb part of thestrength from the ejector pin to prevent from conductive paths occurringbetween the first conductive layer and the second conductive layer 153′,and short circuits due to the conductive paths will not happenaccordingly.

In above embodiments (the eleventh embodiment to the thirteenembodiment), when an ejector pin (not shown) pushes the light-emittingelement, the cushion part can absorb part of the strength from theejector pin to prevent from conductive paths occurring between the firstconductive layer and the second conductive layer, and short circuits dueto the conductive paths will not happen accordingly.

FIG. 14 shows testing data presenting short-circuit ratios oflight-emitting elements of the first embodiment and a conventionallight-emitting element. As shown in FIG. 14, testing quantity of thelight-emitting element of the first embodiment and the conventionallight-emitting element are 846 and 234 respectively. Short-circuitratios of the light-emitting element of the first embodiment and theconventional light-emitting element are zero and 33%. Therefore, thelight-emitting element of the application can prevent short circuits dueto the damage in the detaching process.

The principle and the efficiency of the present application illustratedby the embodiments above are not the limitation of the application. Anyperson having ordinary skill in the art can modify or change theaforementioned embodiments. Therefore, the protection range of therights in the application will be listed as the following claims.

What is claimed is:
 1. A light-emitting element comprises: asemiconductor light-emitting stack comprising a first semiconductorlayer with a first conductivity, an active layer, and a secondsemiconductor layer with a second conductivity wherein the secondsemiconductor layer is disposed on the first semiconductor layer andelectrically connecting the first semiconductor layer; a firstconductive layer disposed on the second semiconductor layer, andelectrically connecting the second semiconductor layer; a firstinsulating layer disposed on the first conductive layer; a secondconductive layer disposed on the second semiconductor layer andelectrically connecting the first semiconductor layer; and a cushionpart disposed on the semiconductor light-emitting stack; wherein in atop view, the cushion part is surrounded by the second conductive layerand electrically isolated from the second conductive layer.
 2. Thelight-emitting element of claim 1, wherein the cushion part is disposedin a center region of the light-emitting element in a top view.
 3. Thelight-emitting element of claim 1, further comprising a secondinsulating layer disposed on the first insulating layer.
 4. Thelight-emitting element of claim 3, wherein the cushion part isinterposed between the first insulating layer and the second insulatinglayer or disposed on the second insulating layer.
 5. The light-emittingelement of claim 1, wherein a material of the cushion part comprisesmetal or an insulating material.
 6. The light-emitting element of claim3, wherein a material of the cushion part is the same as a material ofthe second conductive layer or the first conductive layer.
 7. Thelight-emitting element of claim 1, wherein the cushion part is devoid ofoverlapping with the second conductive layer in a cross-sectional view.8. The light-emitting element of claim 1, wherein a shape of the cushionpart in a top view comprises a symmetrical shape.
 9. The light-emittingelement of claim 1, wherein the cushion part is interposed in the firstinsulating layer or surrounded by the first insulating layer.
 10. Thelight-emitting element of claim 1, wherein the cushion part contacts thefirst conductive layer.
 11. The light-emitting element of claim 1,further comprising a plurality of first depressions formed in thesemiconductor light-emitting stack and penetrating the secondsemiconductor layer and the active layer to expose a surface of thefirst semiconductor layer.
 12. The light-emitting element of claim 11,wherein the first insulating layer covers a side wall of the pluralityof first depressions, and the second conductive layer fills in theplurality of first depressions.
 13. The light-emitting element of claim12, further comprising a first pad and a second pad disposed on theactive layer, wherein the first pad electrically connects the firstsemiconductor layer via the second conductive layer in the plurality offirst depressions.
 14. The light-emitting element of claim 1, furthercomprising a first pad and a second pad disposed on the semiconductorlight-emitting stack , wherein the cushion part, the first pad, and thesecond pad overlap laterally and/or the cushion part is disposed betweenthe first pad and the second pad.
 15. The light-emitting element ofclaim 3, wherein the cushion part is laterally surrounded by the firstinsulating layer or the second insulating layer.
 16. A light-emittingelement comprises: a semiconductor light-emitting stack comprising afirst semiconductor layer with a first conductivity, an active layer,and a second semiconductor layer with a second conductivity; a firstconductive layer disposed on a side of the active layer and electricallyconnecting the second semiconductor layer; a second conductive layerdisposed on the side of the active layer and electrically connecting thefirst semiconductor layer; a first insulating layer disposed on thefirst conductive layer; a second insulating layer disposed on the secondconductive layer; and a cushion part interposed between the firstinsulating layer and the second insulating layer; wherein the secondinsulating layer covers the cushion part and a side wall of the secondconductive layer.
 17. The light-emitting element of claim 16, wherein amaterial of the cushion part is the same as a material of the secondconductive layer or a material of the first conductive layer.
 18. Thelight-emitting element of claim 16, further comprising a first pad and asecond pad wherein the cushion part is disposed between the first padand the second pad.